Thanks for your reply Tom, that's great news about encage functionality for EIAS 10. I can't wait, although you know I've been saying I can't wait for years now.
I've had to stretch the animation even longer to almost 1000 frames so almost 1000 child objects and now EIAS 9.1 is crashing on me after batch converting obj's to fact's which wasn't happening this morning. I can't send a simplified version since I need ALL models smooth when rendered.
I've moved the render to Cinema 4d which is where the modeling took place and that's about all I can do. I really wanted to render in EIAS because of its nice motion blur but I just learnt also that motion blur doesn't work with child cycling so moving the render to Cinema makes total sense now.
Thanks again.